# ---
# title: 1457. Pseudo-Palindromic Paths in a Binary Tree
# id: problem1457
# author: Tian Jun
# date: 2020-10-31
# difficulty: Medium
# categories: Bit Manipulation, Tree, Depth-first Search
# link: <https://leetcode.com/problems/pseudo-palindromic-paths-in-a-binary-tree/description/>
# hidden: true
# ---
# 
# Given a binary tree where node values are digits from 1 to 9. A path in the
# binary tree is said to be **pseudo-palindromic** if at least one permutation
# of the node values in the path is a palindrome.
# 
# _Return the number of **pseudo-palindromic** paths going from the root node to
# leaf nodes._
# 
# 
# 
# **Example 1:**
# 
# ![](https://assets.leetcode.com/uploads/2020/05/06/palindromic_paths_1.png)
# 
#     
#     
#     Input: root = [2,3,1,3,1,null,1]
#     Output: 2 
#     Explanation: The figure above represents the given binary tree. There are three paths going from the root node to leaf nodes: the red path [2,3,3], the green path [2,1,1], and the path [2,3,1]. Among these paths only red path and green path are pseudo-palindromic paths since the red path [2,3,3] can be rearranged in [3,2,3] (palindrome) and the green path [2,1,1] can be rearranged in [1,2,1] (palindrome).
#     
# 
# **Example 2:**
# 
# **![](https://assets.leetcode.com/uploads/2020/05/07/palindromic_paths_2.png)**
# 
#     
#     
#     Input: root = [2,1,1,1,3,null,null,null,null,null,1]
#     Output: 1 
#     Explanation: The figure above represents the given binary tree. There are three paths going from the root node to leaf nodes: the green path [2,1,1], the path [2,1,3,1], and the path [2,1]. Among these paths only the green path is pseudo-palindromic since [2,1,1] can be rearranged in [1,2,1] (palindrome).
#     
# 
# **Example 3:**
# 
#     
#     
#     Input: root = [9]
#     Output: 1
#     
# 
# 
# 
# **Constraints:**
# 
#   * The given binary tree will have between `1` and `10^5` nodes.
#   * Node values are digits from `1` to `9`.
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
